All in all, my game runs a bit smoother with V-sync on (60 fps), than with V-sync off (90 fps). But there are still some "lack". Could there be some things that would make it more smooth?

You could probably set up a long laundry list of things to do:

- Sweep the computer for malware. Sometimes when you accept browser plugins or install certain software, other programs are installed in secret and while these are not particularly harmful and perhaps do not invade your privacy in a way that concern you, they are often resource heavy and while playing games you can notice stuttering while these malicious programs are trying to send data or whatever it is they may be doing.

- On a similar note, sweep the computer for viruses as well. Most antivirus software is garbage designed to scare you into thinking you need to buy their services, but every now and then they catch something that is actually a virus.

- Update all your drivers. ALL OF THEM. The graphics card is the most obvious one, but try others as well. Sometimes it makes no sense, but simply updating drivers can sometimes fix serious bugs and performance issues, even though there is no obvious reason why any particular version is working poorly and why one is perfect.

- I don't suggest formatting and reinstalling Windows from scratch, but... since you bought the computer, have you ever done it? Depending on how neat and tidy you are, and how concious you are about safe internet use, your computer could still be a well oiled machine or it could be a complete mess. You should at least DeFrag your drives every now and then, especially if you tend to download or move around lots of stuff. Defragmentation pretty much means letting the computer re-write where large chunks of data should physically exist on the harddrive so that they can be read faster, rather than having to read small parts all over the drive.

- Try disabling sound in-game. I don't mean just muting or turning off your speakers, I mean disabling all sound processing, perhaps via the game config file. Of course you don't want to play without sound but it can be a good thing to test to see how it affects performance. If the game works fine for a long time without sound perhaps we can start narrowing down the problem.

Also, could you type up your actual computer specs? You say it was an excellent machine back in 2013 but there could still be some bottleneck like a really cheap soundcard or other component that just won't work well with some games.

@Sufyan:
Thanks for the reply.
I do sometimes run a defrag and a disk cleanup.

I used systemrequirementslab, and get the following specs info:
Processor Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz
Manufacturer Intel
Speed 3.4 GHz
Number of Cores 8

Video Card 1 Intel(R) HD Graphics 4600
Manufacturer Intel
Chipset Intel(R) HD Graphics 4600
Dedicated Memory 64 MB
Total Memory 1.7 GB

Video Card 2 NVIDIA GeForce GTX 660
Manufacturer NVIDIA
Chipset GeForce GTX 660
Dedicated Memory 2.1 GB
Total Memory 3.9 GB

Memory 16 GB

Operating System Microsoft Windows 7 Professional Edition Service Pack 1 (build 7601), 64-bit
Service Pack 1
Size 64 Bit
Edition Professional

Display Maximum Resolution 1680 x 1050

DVD TSSTcorp CDDVDW SH-224BB SCSI CdRom Device

CD TSSTcorp CDDVDW SH-224BB SCSI CdRom Device

Drive 1
Size 1.8 TB
Free 859.2 GB

Drive 2
Size 231.9 GB
Free 100.3 GB

Seems you have a proper graphics card (nVidia) and an intergrated chipset on your CPU. As far as I can tell the purpose of the intergrated chipset is to take over when the graphics card is unnecessary like when you are not playing games. MAAAAAYBE the computer mistakenly thinks MOHAA is not very demanding and lets the intergrated chipset render the graphics instead of the graphics card? Long shot, but it warrants investigation.

Does the computer sound different when playing MOHAA than it does when you play a modern game? When the graphics card start working hard you may hear the fan speed up, while perhaps the computer is very quiet when not gaming. If it is quiet while playing MOHAA maybe it is not using the graphics card.

I'm afraid I can't guide you step by step through the technical bits, just throwing out ideas to investigate.

I haven't notice any difference when I play MOHAA. But as I understand it, a total solution will be quite difficult to reach, and I think that the lesser "lag" I experience with V-sync on makes the game tolerable to play, at least until I complete it.
So I think I will consider this problem to be solved.

But thank you very much (both of you) to take the time to help me!

Hi, I'm experiencing this with the opening level of Spearhead. In fact, not only do I experience fps drops on the first level of Spearhead, but the game crashes if I try using an HD mod. What's going on?

"seta r_primitives" has options: 0, 1, 2, 3

Don't play with it. It won't enhance MoHAA game performance.

I started to have black textures bug
(maybe because of that, - even with the line deleted from config, or maybe because of sudden restart)
but deleting unnamedsoldier.cfg (depending on expansion which causes the issue) main (AA), mainta (SPR), maintb (BR) fixes it.

The only thing which somehow works a little is renaming game binary to Quake3.exe.

I found it!

Go to the game main menu, and go to options, advanced, and set shadows to simple, and curve details to low.
It should fix literally all performance problems, especially in Spearhead, when FPS can go down to even 8 FPS in the first level.

I can't believe that solution was so easy...

What deton24 wrote...

This from pcgamingwiki works somewhat.
[url=https://www.pcgamingwiki.com/wiki/Medal_of_Honor:_Allied_Assault#Unstable_frame_rate_and_stuttering]https://www.pcgamingwiki.com/wiki/Medal_of_Honor:_Allied_Assault#Unstable_frame_rate_and_stuttering[/url]
[i]cg_shadows "1"
seta r_subdivisions "10"[/i]

Perfomance is still subpar though. This game really needs a remake to run better on newer OS's.